RF transceivers are used in a variety of modern electronics, such as smartphones, digital radios, modems, routers, printers, and internet gateways. A variety of communication standards have been recently introduced to use over-the-air RF transmission and reception capabilities for relatively short distances, including near-field communication (NFC) having a distance of about 10 centimeters, personal area networks operative from 10 to 100 meters using a protocols such as “ZigBee”, “Bluetooth” and Bluetooth low energy (BTLE), and wireless local area networks such as “WiFi” having a maximum distance that varies based on conditions but under ideal conditions has been measured at over 300 meters. These standards are designed for particular purposes and generally have different power and signaling requirements. However many electronic products now support multiple ones of these standards, and providing separate circuitry for each standard increases product cost. Moreover it is difficult to design low cost, reliable transceivers using a common antenna that provide acceptable characteristics for both transmission and reception, such as appropriate transmit power level and acceptable noise figure (NF) for reception.
The use of the same reference symbols in different drawings indicates similar or identical items. Unless otherwise noted, the word “coupled” and its associated verb forms include both direct connection and indirect electrical connection by means known in the art, and unless otherwise noted any description of direct connection implies alternate embodiments using suitable forms of indirect electrical connection as well.